1. Field of the Invention
The invention is based on a metal-enclosed gas-insulated switching installation.
2. Discussion of Background
Single-phase metal-enclosed gas-insulated switching installation is known which exhibits a double busbar system. As a rule, only a first one of the busbar systems is in operation whilst the second one is taken into operation only when inspections or a fault in the area of the first busbar system require this system to be disconnected from the supply.
For an inspection of a circuit breaker pole, for example in one phase of an outgoing line bay, the extinction chamber of the relevant circuit breaker pole is pulled out of the metal pole housing but this is only permissible when the connections of the circuit breaker pole have previously been reliably grounded. This grounding must take place both on the outgoing side and on the busbar side. In a conventional outgoing line bay of a metal-enclosed gas-insulated switching installation which is provided with a double busbar system, one ground electrode is as a rule necessary in each case on both sides of the circuit breaker pole of one phase for the grounding on the busbar side. After the extinction chamber has been pulled out, these two ground electrodes are no longer metallically connected so that proper grounding is only achieved when both ground electrodes, that is to say one on each side of the circuit breaker pole, are closed. Before the ground electrodes are closed, the corresponding busbar isolators which are in each case arranged between the ground electrode and the busbar are naturally open so that the busbars still remain under voltage as before and can ensure undisturbed operation of the parts of the gas-insulated switching installation not affected by the inspection.
If the busbar isolators are constructed as sectionalizing isolators which extend along a connecting axis, this necessitates a comparatively large spacing of the busbars from the circuit breaker poles which results in increased space requirement for the gas-insulated switching installation.